Background: Weight loss surgery (WLS) outcomes are poorly understood. This study aimed to evaluate the relationship of well-documented (e.g., health, diet, physical activity) and theoretically relevant variables (e.g., substance use and "food addiction") with both weight nadir and weight regain (WR) following WLS.
Methods: A sample of 97 Roux-en-Y gastric bypass patients (M time since surgery = 8.86 years) were surveyed about pre- and post-WLS weight, health, self-management behaviors, alcohol problems, and clinical symptoms.
Results: Patients lost a mean of 42 % (SD = 10.71 %) of total weight at weight nadir, but 26 % (SD = 19.66 %) of the lost weight was regained by the time of the survey. Correlates of lower weight nadir and WR differed considerably, with minor overlap. Weight nadir was associated with pre-WLS drug use and post-WLS medical comorbidities. WR, on the other hand, was associated with post-WLS adherence to dietary and physical activity modification. Post-WLS nocturnal eating, depression, and problematic alcohol use were also associated with WR. With all associated variables in regression models, number of post-WLS medical comorbidities (β = -.313, p < 0.01) and post-WLS depression (β = 0.325, p < 0.01) accounted for the most variance and remained as significant predictors of weight nadir and WR, respectively.
Conclusions: While weight nadir was associated with relatively few and largely nonmodifiable variables, WR was significantly associated with adherence-related behaviors, mood symptoms, and pathological patterns of food and alcohol use, all of which are potentially modifiable. These findings underscore the importance of long-term behavioral and psychosocial monitoring after surgery.